Welcome to Bimmerfest -- The #1 Online Community for BMW related information! Please enjoy the discussion forums below and share your experiences with the 200,000 current, new and past BMW owners. The forums are broken out by car model and into other special interest sections such as BMW European Delivery and a special forum to voice your questions to the many BMW dealers on the site to assist our members!

E46 (1999 - 2006) The fourth generation 3 Series (E46 chassis) was introduced in 1999 and set the standard for engineering and performance during it's years of production including being named to Car & Driver's 10 best list every one of those years! ! -- View the E46 Wiki

I have a 2003 325xi that just turned over 165K (I’ve had the car since 40K purchased in 2005). All is well with the car except that I seem to be going through quite a bit of oil. I usually have to add a quart every 800 miles or so – about every two weeks with the 80 miles a day or so I drive to work. This has been going on for about 6 months – but now seems to be getting worse. I don't smell any oil or antifreeze burning.

I questioned my indy non-BMW specific mechanic about this and he said there was a slow leak in the oil filter housing gasket. At home I park the same place and my car shows no evidence of leaking anything – same situation at work. From reading this forum I know that these engines will use more oil as they get older, but I wanted to check that this sounds normal to everyone here.

I wanted to get the thoughts with the experts here that a ‘slow’ leak in the oil filter housing gasket was the possible cause of my missing oil. I have no problem having the mechanic change out the gasket for me, but there are a couple of other repairs I need to do as well and I just wanted to prioritize things. I love the car and I plan on it seeing 200K.

Just to answer some of the questions I know I'm going to get asked:
-Indy mechanic quoted $300 for changing out the gasket
-I'm 9 months pregnant and live in NH without a heated garage so the chance of me doing any repairs myself for the foreseeable future is nil. (Although I have really enjoyed fixing small things myself and learning how the car worked in the past thanks to this forum).

Leave it to my more knowledgable colleagues for a detailed response, but I had OFHG oil leak earlier this year, and it was obvious it was leaking from just a casual look. If you see no oil around the oil filter housing, your problem is likely elsewhere.

Leave it to my more knowledgable colleagues for a detailed response, but I had OFHG oil leak earlier this year, and it was obvious it was leaking from just a casual look. If you see no oil around the oil filter housing, your problem is likely elsewhere.

I had a leaky OFHG that used about a quart every 600-700 miles, changed it and now it doesn't use any significant amount at all. It may LOOK like a small leak, but any leak should be repaired as soon as you detect it.

I had a leaky OFHG that used about a quart every 600-700 miles, changed it and now it doesn't use any significant amount at all. It may LOOK like a small leak, but any leak should be repaired as soon as you detect it.

Thanks - that must be the case then. I would have never thought it would leak that much.

Thanks to everyone taking the time to respond - I really appreciate it.

Sounds to me that it's a failing crankcase ventilation valve, leaks usually aren't a quart every 1000 miles. Also the common leak places are likely to leak onto hot areas and smell. When a CCV valve fails the car burns the oil and runs slightly more coarse because it causes the vacuum system to work improperly. It's a gradual transition and is pretty unnoticeable until you address the CCV failure and feel the difference.

Here's my quick diagnosis (and I've written this in a few places on this forum already)

1. Take out the dipstick, examine the bottom (usually plastic and colored red or orange) if it for black sludgy oil residue, this is a sign of a failed CCV.
2. While the engine is idling remove the oil fill cap and then put it back on, make sure it't tight. While you do this listen carefully for changes or surges in the engine idle pitch, especially when putting the cap back on. If there's no change in pitch then the vacuum system may be faulty and it's usually due to a CCV failure. You can also remove the dipstick and listen for a change in the engine pitch.

A mechanic with the proper tools would seal a hose on the dipstick tube with a pressure gauge on it and look for negative pressure, if there's no negative pressure, change the CCV, it's not a particularly fun job but it's a common problem on these engines.

Replace your CCV first, then the OFHG gasket if needed. The failing CCV may have also caused your valve cover gasket to fail due to the crankcase being pressurized. Feel around the valve cover to see if the gasket is leaking.

Replace your CCV first, then the OFHG gasket if needed. The failing CCV may have also caused your valve cover gasket to fail due to the crankcase being pressurized. Feel around the valve cover to see if the gasket is leaking.

If you replace the CCV, do the OFHG at the same time. It's very easy, inexepensive (less than $10) and removing the oil filter housing makes it much easier to get to the CCV. The OFHG is a got a limited life expectancy because of its design , so even if it's not leaking now, it will sooner or later. Consider it preventative maintenance.

Here's my quick diagnosis (and I've written this in a few places on this forum already)

1. Take out the dipstick, examine the bottom (usually plastic and colored red or orange) if it for black sludgy oil residue, this is a sign of a failed CCV.
2. While the engine is idling remove the oil fill cap and then put it back on, make sure it't tight. While you do this listen carefully for changes or surges in the engine idle pitch, especially when putting the cap back on. If there's no change in pitch then the vacuum system may be faulty and it's usually due to a CCV failure. You can also remove the dipstick and listen for a change in the engine pitch.

A mechanic with the proper tools would seal a hose on the dipstick tube with a pressure gauge on it and look for negative pressure, if there's no negative pressure, change the CCV, it's not a particularly fun job but it's a common problem on these engines.

If you replace the CCV, do the OFHG at the same time. It's very easy, inexepensive (less than $10) and removing the oil filter housing makes it much easier to get to the CCV. The OFHG is a got a limited life expectancy because of its design , so even if it's not leaking now, it will sooner or later. Consider it preventative maintenance.

That's a good point, and good advice. I must be still hung over from Christmas!